A resin-made container that contains a drink, cosmetics, a chemical, a cleaning agent, or toiletry items such as shampoo or the like can be attained by blow-molding a resin-made preform formed by injection molding or compression molding or the like. In such a case, generally, the preform used in blow-molding is equipped with a circular mouth, and a circular, closed-end body, and is constituted to be equipped with a circular and flange-shaped neck-support between the mouth and the body.
Conversely, a liquid-blow molding apparatus is known as a blow molding apparatus that blow-molds a preform by supplying a pressurized liquid into the preform, thereby liquid-blow molding the preform. The liquid-blow molding apparatus is equipped with a circular nozzle; the apparatus is constituted to insert the nozzle into the mouth of the preform, and to supply pressurized liquid into the preform through the nozzle. With this kind of liquid-blow molding apparatus, it is possible to use a liquid, such as a drink or the like, to be contained in the container as the final product, as the pressurized liquid that is supplied to the preform. For that reason, it is possible to simplify production and the construction of the blow-molding apparatus by omitting the process of filling container fluid into the container.
A nozzle in the liquid-blow molding apparatus is inserted into the mouth in the preform, and is loosely inserted with a slight gap to an inner face of the mouth to make detachment easier. For that reason, a sealing structure is disposed in the liquid-blow molding apparatus to prevent liquid supplied inside the preform through the nozzle from leaking to the outside from between the outer face of the nozzle and the inner face of the mouth.
For example, disclosed in Japanese Unexamined Patent Application Publication No. 2014-128911, hereafter “patent document 1” is a liquid-blow molding apparatus that mounts a circular sealing member to a base end of the nozzle to block the preform mouth by touching the sealing member to the open end of the mouth when the nozzle is inserted into the mouth.